1 //===-- WinException.h - Windows Exception Handling ----------*- C++ -*--===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains support for writing windows exception info into asm files.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
14 #define LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
15 
16 #include "EHStreamer.h"
17 #include <vector>
18 
19 namespace llvm {
20 class GlobalValue;
21 class MachineFunction;
22 class MCExpr;
23 class MCSection;
24 struct WinEHFuncInfo;
25 
26 class LLVM_LIBRARY_VISIBILITY WinException : public EHStreamer {
27   /// Per-function flag to indicate if personality info should be emitted.
28   bool shouldEmitPersonality = false;
29 
30   /// Per-function flag to indicate if the LSDA should be emitted.
31   bool shouldEmitLSDA = false;
32 
33   /// Per-function flag to indicate if frame moves info should be emitted.
34   bool shouldEmitMoves = false;
35 
36   /// True if this is a 64-bit target and we should use image relative offsets.
37   bool useImageRel32 = false;
38 
39   /// True if we are generating exception handling on Windows for ARM64.
40   bool isAArch64 = false;
41 
42   /// True if we are generating exception handling on Windows for ARM (Thumb).
43   bool isThumb = false;
44 
45   /// Pointer to the current funclet entry BB.
46   const MachineBasicBlock *CurrentFuncletEntry = nullptr;
47 
48   /// The section of the last funclet start.
49   MCSection *CurrentFuncletTextSection = nullptr;
50 
51   /// The list of symbols to add to the ehcont section
52   std::vector<const MCSymbol *> EHContTargets;
53 
54   void emitCSpecificHandlerTable(const MachineFunction *MF);
55 
56   void emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
57                               const MCSymbol *BeginLabel,
58                               const MCSymbol *EndLabel, int State);
59 
60   /// Emit the EH table data for 32-bit and 64-bit functions using
61   /// the __CxxFrameHandler3 personality.
62   void emitCXXFrameHandler3Table(const MachineFunction *MF);
63 
64   /// Emit the EH table data for _except_handler3 and _except_handler4
65   /// personality functions. These are only used on 32-bit and do not use CFI
66   /// tables.
67   void emitExceptHandlerTable(const MachineFunction *MF);
68 
69   void emitCLRExceptionTable(const MachineFunction *MF);
70 
71   void computeIP2StateTable(
72       const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
73       SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable);
74 
75   /// Emits the label used with llvm.eh.recoverfp, which is used by
76   /// outlined funclets.
77   void emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
78                                      StringRef FLinkageName);
79 
80   const MCExpr *create32bitRef(const MCSymbol *Value);
81   const MCExpr *create32bitRef(const GlobalValue *GV);
82   const MCExpr *getLabel(const MCSymbol *Label);
83   const MCExpr *getLabelPlusOne(const MCSymbol *Label);
84   const MCExpr *getOffset(const MCSymbol *OffsetOf, const MCSymbol *OffsetFrom);
85   const MCExpr *getOffsetPlusOne(const MCSymbol *OffsetOf,
86                                  const MCSymbol *OffsetFrom);
87 
88   /// Gets the offset that we should use in a table for a stack object with the
89   /// given index. For targets using CFI (Win64, etc), this is relative to the
90   /// established SP at the end of the prologue. For targets without CFI (Win32
91   /// only), it is relative to the frame pointer.
92   int getFrameIndexOffset(int FrameIndex, const WinEHFuncInfo &FuncInfo);
93 
94   void endFuncletImpl();
95 public:
96   //===--------------------------------------------------------------------===//
97   // Main entry points.
98   //
99   WinException(AsmPrinter *A);
100   ~WinException() override;
101 
102   /// Emit all exception information that should come after the content.
103   void endModule() override;
104 
105   /// Gather pre-function exception information.  Assumes being emitted
106   /// immediately after the function entry point.
107   void beginFunction(const MachineFunction *MF) override;
108 
109   void markFunctionEnd() override;
110 
111   /// Gather and emit post-function exception information.
112   void endFunction(const MachineFunction *) override;
113 
114   /// Emit target-specific EH funclet machinery.
115   void beginFunclet(const MachineBasicBlock &MBB, MCSymbol *Sym) override;
116   void endFunclet() override;
117 };
118 }
119 
120 #endif
121 
122